Sony STR-GX10ES tuner in Japanese mode
 

This Sony STR-GX10ES receiver works great apart from the tuner seems
to be in the wrong mode. It tunes from 79-90 MHz on FM and 522-1611
kHz on AM in 9kHz steps. I think this is the Japanese FM band.
There's no obvious switch for changing tuning modes and I'm sure this
receiver was made for the US market (120V with the manual in English).
It doesn't respond to the key combination that's supposed to switch
between 9kHz and 10kHz AM spacing. Is there a key combination for
changing it back to US tuning mode? I remember seeing such
combinations in the service manuals to other Sony receivers, but I
don't have the service manual to this one.
Andy Cuffe

I'm not finding this info on this model. I guess you tried the "channel-up"
or "channel down" while plugging in, this changes tuning steps on some Sony
models.
A Yamaha receiver I worked on did this - it was a bad micro, since the
tuning region options were hard-wired with jumpers.

Mark Z.


"Andy Cuffe" wrote in message
...
This Sony STR-GX10ES receiver works great apart from the tuner seems
to be in the wrong mode. It tunes from 79-90 MHz on FM and 522-1611
kHz on AM in 9kHz steps. I think this is the Japanese FM band.
There's no obvious switch for changing tuning modes and I'm sure this
receiver was made for the US market (120V with the manual in English).
It doesn't respond to the key combination that's supposed to switch
between 9kHz and 10kHz AM spacing. Is there a key combination for
changing it back to US tuning mode? I remember seeing such
combinations in the service manuals to other Sony receivers, but I
don't have the service manual to this one.
Andy Cuffe

On Thu, 23 Dec 2004 06:19:50 -0600, "Mark D. Zacharias"
wrote:

I'm not finding this info on this model. I guess you tried the "channel-up"
or "channel down" while plugging in, this changes tuning steps on some Sony
models.
A Yamaha receiver I worked on did this - it was a bad micro, since the
tuning region options were hard-wired with jumpers.

Mark Z.



Yes, I tried all those combinations. It looks like I will need the
service manual to get anywhere. If anyone has a paper copy they could
scan, all I should need is a scematic of everything around the main
micro controller.

Andy Cuffe

Sony's service website is down, can't download the PDF. Assuming:

1. It's available,
2. Contains a schematic (older units may not)
3. You can take a large attachment

I'd be happy to send it to you.

I'll check back with their site Monday, it's been down since Friday.

Mark Z.
"Andy Cuffe" wrote in message
...
On Thu, 23 Dec 2004 06:19:50 -0600, "Mark D. Zacharias"
wrote:

I'm not finding this info on this model. I guess you tried the
"channel-up"
or "channel down" while plugging in, this changes tuning steps on some
Sony
models.
A Yamaha receiver I worked on did this - it was a bad micro, since the
tuning region options were hard-wired with jumpers.

Mark Z.



Yes, I tried all those combinations. It looks like I will need the
service manual to get anywhere. If anyone has a paper copy they could
scan, all I should need is a scematic of everything around the main
micro controller.

Andy Cuffe

On Thu, 23 Dec 2004 06:19:50 -0600, "Mark D. Zacharias"
wrote:

I'm not finding this info on this model. I guess you tried the "channel-up"
or "channel down" while plugging in, this changes tuning steps on some Sony
models.
A Yamaha receiver I worked on did this - it was a bad micro, since the
tuning region options were hard-wired with jumpers.

Mark Z.



It turned out to be caused by a bad memory backup cap. Removing the
old one was enough to reset it to US tuning mode. Installing a new
one has it working as it should. I guess the voltage was low enough
to corrupt the memory, but not low enough to reset it.

Andy Cuffe

Wow. Seeing this reminds me that Yamaha's have had bad backup caps which
leaked. Could yours have had leakage from the cap on the board?

Mark Z.


"Andy Cuffe" wrote in message
...
On Thu, 23 Dec 2004 06:19:50 -0600, "Mark D. Zacharias"
wrote:

I'm not finding this info on this model. I guess you tried the
"channel-up"
or "channel down" while plugging in, this changes tuning steps on some
Sony
models.
A Yamaha receiver I worked on did this - it was a bad micro, since the
tuning region options were hard-wired with jumpers.

Mark Z.



It turned out to be caused by a bad memory backup cap. Removing the
old one was enough to reset it to US tuning mode. Installing a new
one has it working as it should. I guess the voltage was low enough
to corrupt the memory, but not low enough to reset it.

Andy Cuffe

On Fri, 7 Jan 2005 04:33:34 -0600, "Mark D. Zacharias"
wrote:

Wow. Seeing this reminds me that Yamaha's have had bad backup caps which
leaked. Could yours have had leakage from the cap on the board?

Mark Z.


There was no leakage on the board, but it seemed to be confusing the
micro. I've seen this before when the backup cap was failing. The
worst was an 80's Fisher Hi-Fi VCR that would completely lock up in a
power failure. The only way to make it work was to hold down a hidden
reset button while plugging it in. Replacing the backup cap fix the
problem. You wouldn't think a defective cap would be any worse than a
fully discharged cap, but in some cases it causes weird problems.
I've seem dozens of defective Elna and Panasonic backup caps, but I
have never seen an NEC cap fail.
Andy Cuffe